The present invention relates to a metal detection device.
A metal detector on a forage harvester for detection of metallic foreign objects in crop material is disclosed in EP 0 702 248. The metal detector is located in a lower feeder drum and is composed of three magnetic windings positioned across the width of the feeder drum. To enable better determination of the position of the metal object, a signal processing unit generates differential voltages that correspond to the differences between two of the three individual voltages produced by the windings, and compares the differential voltages with each other and with a threshold value. It also calculates the sum of the winding voltages and generates a confirmation and/or trigger signal when the sum of the voltages is greater than a specified threshold value, by way of which the shut-off device for the feeder drums is actuated, and an alarm and/or display unit is switched on.
The disadvantage of this known harvesting machine is that it is only capable of detecting, using the metal detector, the position of the metal object across the width of the metal detector at the instant the threshold value is exceeded. With metal detection devices having this design, the movement of the metal object until the feeder devices come to a standstill is not taken into consideration.